diff --git a/lib/MilkCheck/UI/Cli.py b/lib/MilkCheck/UI/Cli.py
index a854c0e..06a63df 100755
--- a/lib/MilkCheck/UI/Cli.py
+++ b/lib/MilkCheck/UI/Cli.py
@@ -452,7 +452,7 @@ def run(self):
 
     def join(self, timeout=None):
         '''Only join if thread is alive'''
-        if self.isAlive():
+        if self.is_alive():
             threading.Thread.join(self, timeout)
 
     def quit(self):